In a prior art, in order to play back images, such as movies and advertisements in a theater, a two-dimensional (2D) image is projected on a single screen disposed at the front of a movie theater. In such a system, audiences inevitably experience only 2D images.
A 3D image-related technology capable of providing a stereoscopic image to audiences has recently been developed. The 3D image technology is based on a principle that when different images enter the left eye and right eye of a person and are merged in a brain, the person is able to feel a three-dimensional effect even in a 2D image. In such a 3D image technology, two cameras on which different polarization filters are mounted are used to capture images, and glasses on which a polarization filter is mounted is used so that different images enter the left eye and right eye of a person when the person watches an image.
However, such a 3D technology may provide a stereoscopic image to a user, but is problematic in that a degree of immersion for an image itself is low because a user merely watches an image played back in a single screen. Furthermore, there is a problem in that the direction of a three-dimensional effect felt by audiences is limited to a direction in which a single screen is placed. Furthermore, the conventional 3D technology is problematic in that it may cause inconvenience for audiences who watch images because the audiences must wear glasses on which a polarization filter is mounted and that sensitive audiences may feel dizzy or sick because different images are forced to enter the left eye and right eye of a user.
Accordingly, a so-called “multi-projection system” (a preceding application of this application) capable of solving the problems of a conventional screening system based on a single screen was proposed. In this case, the “multi-projection system” means a system in which a plurality of projection surfaces (e.g., a screen and the surface of a wall) is disposed in the vicinity of stands and images having a sense of unity are played back on the plurality of projection surfaces so that audiences may have three-dimensional effects and immersive experiences. Furthermore, a “multi-projection theater” means a theater in which such a multi-projection system has been constructed. FIG. 1 illustrates an example of such a multi-projection system.
In order to effectively manage the multi-projection system, there is a need for technologies capable of effectively correcting images projected on a plurality of projection surfaces. The reason for this is that in the multi-projection system, an image correction process is very complicated and it is very likely that an error may occur because a plurality of images projected on a plurality of projection surfaces not on a single projection surface needs to be integrated and corrected and a method of correcting a plurality of images needs to be changed according to a change in the structure of a theater. Accordingly, there is a need for technologies that may assist the image correction process of such a multi-projection system.
In addition to such a multi-projection system, images may be projected on a single projection surface using a plurality of projectors. For example, images may be projected on a single projection surface using a plurality of projectors if the width of a projection surface is wide or if a length-width ratio of a projection surface is not handled by a single projector.
If images are to be projected using a plurality of projectors, it is very important to provide images having a sense of unity. In particular, images need to be corrected so that the boundaries of images or the overlap area and non-overlap area of images projected by respective projectors are not distinct.